class Solution {
public:
    int removeElement(vector<int>& nums, int val) 
    {
        int left = 0;
        for(int i = 0;i < nums.size();i ++)
        {
            if(nums[i] != val)
            {
                nums[left] = nums[i];
                left ++;
            }
        }
        return left;
    }
};